SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c7d1c6260a9b20dc7aa33988d8bf7802ece1c0eb59afc23468fc8b068e29876' 
  AND token = 'EP/cpZaxN3pqvV/zmvtyK2/I1NiC5BPhBazJZiz8eg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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