SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '689ecc8edadc60ad631101b95514f0138a67225c70d3e71faaf4904f4abde1f6' 
  AND token = 'IN1yz0cRmJbcUu3gv+aIAE/ls3SErPzX6YiFx8euOxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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