SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df94e66e2a7f12ca083cb76ec399f2e1d2d47caaa25e673138541619cf0c2a35' 
  AND token = 'Os8Adm6EBW2R1ALV2qowarTueo+1Z+usM30hfTwYogI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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