SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e6ebfd5669c3d0646eecd5b2fea56bb735ef3fb21e73e5dea91dade2f04717a' 
  AND token = 'pTH2P5SnfnBMMRmMo2KIb6wD7KccBBBr2bTWT6XGlc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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