SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3be61e1941df0c9f89c38a3792a9164e9555cede4589d265b07f2478bdf8cefe' 
  AND token = 'weGPbwo0bKUf4PZSm2pqYZ3rhADctFv+rbjPCKtuFFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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