SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4a597b53dc39176263cbbc6358e2c093eec6903375f25eb795e98e0fab17a423' 
  AND token = 'wRLPvoQpLaulM3PytqsmwcaDIfqBjl0AIjvuNanK9eM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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