SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56a52b42a7621fc208da68dd4589c31f8312dadce6d7ecd86d95d8601242ac33' 
  AND token = 'DJ7uTird/W4Yt4ot0jD2xqI85WC1cfP33izvMKYaxqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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