SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8d1150a88c5b334ee0967489b89ea7ebd7a2a63091919955d4292669d6d493e' 
  AND token = 'PbjuHNuolsDw9ZAV1lfg3uwGIkAv6FpiBETv3m+tXio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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