SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c8d39d2d146b9218d0955697d2b39cfb1d936da4f8878520892c17c5d378ee3e' 
  AND token = 'nlCyIP6RDvQTS8yT157+wuW/puOpXsVHKVw9ANqa6D4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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