SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e23f6dea3d3a381591f93db20197182513b7f20e835e9479ef8fa40962e3c58d' 
  AND token = 'AM6Lnljm2/JWQo07LO2NcM0Ss5pJO+ZJQ9I9GAnu31o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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