SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1903aa09e0927d47d4079d0cedf342eb750a09479539eca466d278fb0501fb29' 
  AND token = '91j9YqZJQxbdIS4GGxqdA1tMtK2Vc+kgqHI/1d2FRUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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