SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91144a83ad615fd2550cead4a1bbbfe89958d034e5376a85ca230c3a0e92b025' 
  AND token = 'zDdf23G6SxWjwHuu/Bhd1Ays2HIuJfF+mG5c0koriqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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