SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a20b3e5bfb66fb90332cf8dd28152f0e86e51ca05aebcdab18e794f6bb78da0' 
  AND token = 'I+HYawjUYMv0R+2GuXLmsUu8boIFk9MBhtV0MlbFIG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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