SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b529100ecb4f608d14f5a07dc33d72314c7f2932b49e3849855f3fc3325a99c' 
  AND token = 'IcZ9/iyq1ReVSbfuFpVbsxWpApg+mXxkxM/TGYbXIDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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