SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bccf7b8523a969794f8110683b1a94fbfcc2e166e7b624037c49b56b22ea4bda' 
  AND token = 'Ix18VjPD9KTEO7JK7vhhwxbFYbExJoAm0/7yOCA3eRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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