SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f54d71c2cdef90ece2c203ec1c0c0cb17cf84e68688532eb88ab9b3b14ec7876' 
  AND token = 'T2s/S2WtXT7wHqayxBPwuyViVvoH+RQlqEipgxF8lDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}