SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '142a655a70b3a2248b91e7c058fb89f0b2b5329e58c687705b9d3f06ac612393' 
  AND token = 'VutIBNIWTRtC/DMppchbjE0pZQf3Hr8qJlox+JgD25M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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