SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c6f33fce5319675fe2541501c481b22c1228e212cdbacb8f3d41485b6f73545' 
  AND token = 'q1UrGFvICO61po8h7CFTMwYL4+NCjMX/6mlZ6rr3ZW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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