SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '975e08cc297fa623ea500f55728bb603b78ad17031936ea4813aec865957057a' 
  AND token = 'sct4s80ZjdbXpDz7m+OL+cW5usz5+ScvUQLO6L8GVuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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