SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '588a19a61eb582f5dc4bf5f622eca298108143f7540b478590ca3c8d6e3adf10' 
  AND token = 'mv4RP/8O9Zjwik6S/ulqZtujsVITvqlZwGQ0cHMPU44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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