SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbc0932635cd99eac05fd329089a906bb07e963ac1dca490381f8798264ff7cb' 
  AND token = 'W6plSVOOWsrwjuLry+vlVwZUr8/2X1UUwBgATcYHeo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}