SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '490c8a8af9853698ff9fc5e07800caf8fd84bd62dcf7f034dbf123dba0ca4f5a' 
  AND token = '5TiML1TQqCkL2DFoleiYqQSMbxX4RV4JK/lq0rmo7W0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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