SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '774ed2e03bf588e483f71e6f47c0296e7911fde9cbd5202fd10cadef52c15a73' 
  AND token = 'pkKWqqviP9QBICrBG5dgA10MfqHcmseXaObck1rZzSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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