SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb834582c9177c0472af3fa6f1ef7d33469d588fcbc7fd5650756cd43d47c5e1' 
  AND token = 'oChB9RqRu9PLBcj7Z/D5f2mMKJPQUj0p/HeVFykN0tE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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