SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13a5bb2a9ac54dc8c4f5f17f0973ba55d3fc810ccf487f5b4da3bb43e8d7abe5' 
  AND token = 'f+BQugyHzARpRkPcdmwWhCyaS8NgjRACknLtbo+2Ivg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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