SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f780a3c5d20452f2007cf7abdb637e9d6e028cf8eb60dd57f438d3a38283a2bf' 
  AND token = 'HMYmb7Bwt/W2cddJxZOM8bDc0poiXOhWGCkXfpPmBR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}