SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7add4464f11c8c964775315a8002fe826a3e8e923517b36b99b0b12ea5e1c7a9' 
  AND token = '9jx/D4OMpJOKm+Gpks5fhrKE0g+lenVhsqseL+962XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}