SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fb639709a86926f6a138fafd98c32a75f02357ffb0162dbca22a1ff9b5574346' 
  AND token = 'GjwhvrTDtxa6tmpG1sXybOE82muAXbMW7HaT/aQAYLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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