SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1201b248ab758ce8d7ab94a4af8cc27656d9fe3355383d7e819a3c8be6b542a' 
  AND token = 'HKRuI3s43vhRsU9fxmo/cP08L8f6LfE8S1AG4cOYX+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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