SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '76698479604a8cc2242fc0fd09f19dd37f703719d4f2d56cd7aebd17783af9be' 
  AND token = 'oSk+MRN/m10R3uIjWZa/9jvWdG/00tiPgc+BVLXLJn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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