SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e55f3914ab2db3bd797cf9163555600d4a7b34a909bfd313523f900eb182ce54' 
  AND token = 'jmxLKHfzWeBW940slkKi1BaKgWpfzTuMwPyz1orz0jM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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