SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15ab5cc4b0c14bf3f3d6cd00d07bbf1d91b145556c77397cf8114a9bb7c4bff' 
  AND token = 'stjpADZ5vamoW/2nbtWi8EFatPJyXLVDXNFwFLOWciw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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