SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ab9907626197633eae8f0c71890ad41f83d3a521b6db057fbc96f605177fe1' 
  AND token = '6yQec3d/5MbHcBTo9QGYkPPbpnHC5l8/YKoldcBtCzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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