SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd2b69236dc08849c06af9b6ba0821b0c6acfcc7a4e0b21e739283e932f1e4452' 
  AND token = 'n3uJ1YwvotLTCR7qFwKp+wq9yBRjzOdlTifm3Egu4TM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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