SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e871b799e3539183b66cef233465df7787ba7ae372ed0fd5d5862bdf7c3c6c2a' 
  AND token = 'c1lqRWSQhBOMSiva1xbXkYKy3riIRlYNnj7topUescQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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