SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '860439b4ce96b67789aa3d6cef71df7b71458c9fd5bc65200f98a3ad2a98fdff' 
  AND token = '1JpU4Tazv3e+taPErzDBZFJYSXIgsa6KPMolmCcFqeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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