SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56505813978e049f9147caca81803ee27029bc1678d6013a834e2ea0bbe94c70' 
  AND token = 'vfhBfwozfpsOiuoFlerYF/FdB+fTi2Wi6puDL/4tKGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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