SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7822b678ec0de2c6574dd6ed5746dd0c212258e699d21b33679e7562540aae9' 
  AND token = 'OIg4eamotMYrpxtVoAMMHcL5HhjBKAwSgLigCQgO/j8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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