SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19c74f65ef85837861a72a884c88725ce749271e0260f458f26e21844b380e25' 
  AND token = 'BygVP+BuUw75HkUWj1VSXMGUDy+R3RiayWw3G9ZA7tQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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