SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56f087297bd8e0f688ade2f96434a6ce0396e898d11beac87f52f1969ea9f09c' 
  AND token = 'sXZfyIOtmCCxPIPP3rpRuE/9sJ0Ubzv3uC1WOMeYSH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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