SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9af904cb18217d83b2d6eca00897ff234acdcd679655f1d8fa397bb712084a9' 
  AND token = 'sm2FVnw6dhU8ADT1ZTjUVVUOsyK1kqcUHH7JVjTqyXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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