SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4f59475988f2edbfa8b0d9a4075bb349b2d1057032a05ce0e820c69dc76bbbb' 
  AND token = 'Tsa2f9u6/ojPGyS4/MCcuHRD6Kyh+nDwNcMyudtRx/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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