SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0d553fc363fe2c16570764986128d6c591c6cfccb8d234be80b56c5cd493234' 
  AND token = 'X048eM33xV0JamD3lwrqk7xnT9FGm6TSOGUQ35Ps9Y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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