SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e8e4ff50d0cd9447af574139c6fe6f758bce129d9166b08102b8745e93eed8f' 
  AND token = 'Vh+KP92spL8zKcDLEVdUvAsvSVzSM4PMdgGnclZ1/LY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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