SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '402f94788218d9f5db9bb974dc163fd0b51934431af43cbcbbdcfc21566dd592' 
  AND token = 'lCfOHA5vA7XsPesuKYgZ+z6DMjLqPj6AGtqgIaaYFl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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