SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28f4f0b861df3c7ab72de7f4a7b59aaffddd818a103542f5b42f7b21edd8b74a' 
  AND token = 'GvvO3989o1SJMEe58ZYGA3FuN9ai9/MrmQfd2jf0FcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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