SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d4f716b1a841b06781a5cb2e617e9bb592b578364a1282695ca83b2c5be408f' 
  AND token = 'b5QUOmliwUhIo8aWIOdhV3zmjFLR1OO+TuLsyKlMye0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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