SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '505392a6e0d0b0e9a1de2179df59aa95e0de904135fe196bc295b142cd7112b1' 
  AND token = 'FvGgSDQuFBWfzEC/fs51w9fOCDoKHbhr8Fc3UJw3NzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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