SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20ab3251d81178c86ca7ef5998fb91eec867eb59f23d263a604367a55bfab817' 
  AND token = 'DIJLmMAcqwQrex+Pqzf9Rq56qB/7o7NCAs35oK1Q6jo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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