SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38548dd39e4e3c4d648bd7854d7e8c57a111f60139d0294ef3d75a04dc2264dc' 
  AND token = '+USYcZXLwc6OTUJoGst7CMoALL66TVceAs9jBkJ4fsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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