SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f5524bcfd583583ffb34449c9d56fc19a98ddcf3b21f4ced7c20e37b06e9737' 
  AND token = '+VGGagXhGKwtx1+UWru2A5zm3Wx9UZYFzutT/IhnpNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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