SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36c1d46721bfd484aebde696d54deaf32f5cdfa8d37916b2d6822e7637848a0e' 
  AND token = 'f6nFijQVfy+EKWSS4LMBGjX8PPJ9Ev2GPHaPmTqWhcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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