SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6d6342c747505f0c8bc58d4b470276c13ab23a8f581f4fb19d9bda779d62f12' 
  AND token = 'DYVmwYhHg4Cg1RxaC65ZPD31T55hQ1F+cHRYiuEvKs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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