SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f628df4019f59950332994ce9162df95bd3a66ed3753b06c4ae4aaa3f17ede04' 
  AND token = 'c7Wx271wDPrjRc9CkRJjP2CJQ3AonaeMAK5LuAZiKmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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