SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c5727c67589c529d1191107f5bc9aa3f4f10bb88f21cf746304add763b8b281' 
  AND token = '0ikuBHLOulKgPxuwb2PgJOOC/tct9/zYnEIunDbJXKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}