SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '577aa363f7b0210c06f604486d1cb221eeabb87f1d2f5594bdaba179456c39fc' 
  AND token = 'bkcq+JnFOrn1OXGeImEzNxiCdQgpq+AfqwPqHTyCau8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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