SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8c64eb2b1e170b5e44532e05128f6921c816e652a6f2884976bdb9ab0d4ccd5' 
  AND token = '9U3bYdhe/3a9vx2jYq3g7FkZhLz9ybQcWSYl7zv2kTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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