SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bcdfa13ca9cf88a1c745d163c00331bfaa390ed15bbda5559fd49b4a6b5ccbb' 
  AND token = 'jM2jQPQtFqFD9VWi6otmHpYKW5EmyYrycQEnrmkt/Ng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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