SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5bb4cddebc5f101bc0ed783814a73c62d98fcdb486ef07a1abf1c4392a2d27b' 
  AND token = 'GSFKlSJAPlsLZYqQyAR+oMPtulHzIqHGKxYyvZ5YrD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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