SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '737582811693433712ea9d56e50391347b839da1ab6e6aab4b2f848f7e915a36' 
  AND token = '9/CbB8N+6GqNX1oVY42izpBQMZ72xvReUCVv6YoD61k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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