SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '399a6d217825078cc99c718bd03b2a2cd58ea02024f4a2c7b83779ac3df5059f' 
  AND token = 'wAm6HI5KnFnEPuzqmm2juq+rk4mJGgdUGEKIhUouqEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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