SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4475fe733e90b25aaa21ca03d01c12d9de99454844b7a4499e69e2524a02c0b3' 
  AND token = 'RjSZQAaYkqW2w57ArK15wCnVx3RCj/eY0TnJjYB1c40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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