SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca3cdaba5e79c79fdcce312780d04eb598f54542c73cbb383ff8456088455871' 
  AND token = 'u0EnzUuXXVTUqE291x3B3nVBs0b6bnWAPvYBl2Mszyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}