SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0da9210567ad80f033aec51189f12bbe14a81de24608a332d173bcf6968242f' 
  AND token = 'uX80tOkmTAVkwwLZBXm0KZ3xI8m2NbjD/CjUopUPAF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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