SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e250e36293f6c409f94ae079fafeb000fd078d9114a40024498afa72a251a0c' 
  AND token = 'BZpBaLXTpHtY6Uqhjfg40Lf4X5wskWFAJ3ovabMfPjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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