SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4351ba5a3e19b33ceccc1ecee63eb5c93009cb0d9b564a232a4793ad937139b7' 
  AND token = 'oWr4u/hTnJeBODRq6QsVS4Qw3n8uCGNHO70bNRDfzEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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