SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f63d5bc56dc7508e316344017b8606915d6d0aaac9a7c6c13a9524ae2d98fb24' 
  AND token = 'To1l15e0ml7sCxCzJWPMwc+l9rgSO5lXvdFxriM734I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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