SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a6b9b27b2a4350788812f3a2524e99cddfe4df2c98bac26d064531824970172' 
  AND token = 'YZaBOwImhTpKUnlMCslXx9svTluX1QkB4aAlpFg0Z8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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