SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '894811532c074517a796fb7cb69ca1d75d6c9d6d74039e80b2db30e49210db80' 
  AND token = 'mgcu6o1SLyc/v77OwuwZ6fuYNrqMTV+qphRPZVXbUfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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