SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3398f5665ae93e9d89c80b2b47fe1203a4897427477e23e87f3029d5b66421dc' 
  AND token = 'cuQ8+hSAZEIV5javjPGnF9uQqukOyUrfkijqKrmBZIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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